Using the Example in the Liquid Crystal I2C Library "Hello World" all i get is a bunch of meaningless characters on the screen. I have checked that the correct pins are connected and that R2 jumper is soldered for I2C comm.

That library will not support that LCD, if you look at the datasheet it seams to have a custom driver that is not hitachi driver compliant. Two options:1. Write your own library to drive the LCD2. Google one and see if someone has already writen one.

That library will not support that LCD, if you look at the datasheet it seams to have a custom driver that is not hitachi driver compliant.

Not exactly - but the result is the same. According to the datasheet the board uses a Sunplus SPLC780D controller which, as far as I can tell, is indeed compatible with the HD44780 instruction set. BUT - there is also a PIC16F690 that is converting the serial input information into commands for the controller chip. So the library will not support that LCD because that particular PIC interface is not supported by the Liquid Crystal I2C Library.

What about the library listed on this page for New Haven (LCDi2cNHD) Displays, it seems they also use the PIC 16F690 Interface ?

That's a (very slim) possibility. The PIC 16F690 is nothing more than a garden variety microprocessor, not unlike the ATmega328 in your Arduino. It can be programmed to interface the LCD display with any variety of serial communication protocols. If the commands for the New Haven serial interface happen to match match the commands for your serial interface (not likely) then the library may work.